From: Kris Van Hees <kris.van.hees@oracle.com>
Date: Mon, 22 Dec 2014 21:56:13 +0000 (-0500)
Subject: dtrace: add support for sparc64 1of3
X-Git-Tag: v4.1.12-92~313^2~29
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=91352d1f425720035944364907ff81ef921bc438;p=users%2Fjedix%2Flinux-maple.git

dtrace: add support for sparc64 1of3

This commit is the 1st of 3 commits to add DTrace support to the sparc64
kernel.  This particular commit covers the sparc64-specific kernel code
changes.

- Set ARCH_SUPPORTS_DTRACE for SPARC64.

- Add DIE_PAGE_FAULT to be used in the (new) notifier call in the
  do_kernel_fault() function to allow DTrace to report failed memory
  accesses from probe recipes as an error rather than causing a kernel
  OOPS.

- Add support for the dtrace_no_pf() functionality to ignore page faults
  on request when trying to access userspace.

- Add support for the waitfd syscall.

Orabug: 19005031

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Nick Alcock <nick.alcock@oracle.com>
---

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index e49502acbab40..24d07458c5a77 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -150,6 +150,9 @@ config PGTABLE_LEVELS
 	default 4 if 64BIT
 	default 3
 
+config ARCH_SUPPORTS_DTRACE
+	def_bool y if SPARC64
+
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"
diff --git a/arch/sparc/include/asm/kdebug_64.h b/arch/sparc/include/asm/kdebug_64.h
index 04465de8f3b52..d5b482dd1847a 100644
--- a/arch/sparc/include/asm/kdebug_64.h
+++ b/arch/sparc/include/asm/kdebug_64.h
@@ -16,6 +16,8 @@ enum die_val {
 	DIE_CALL,
 	DIE_NMI,
 	DIE_NMIWATCHDOG,
+	DIE_GPF,
+	DIE_PAGE_FAULT,
 };
 
 #endif
diff --git a/arch/sparc/include/uapi/asm/unistd.h b/arch/sparc/include/uapi/asm/unistd.h
index 6f35f4df17f28..9149cc8742b03 100644
--- a/arch/sparc/include/uapi/asm/unistd.h
+++ b/arch/sparc/include/uapi/asm/unistd.h
@@ -416,6 +416,7 @@
 #define __NR_memfd_create	348
 #define __NR_bpf		349
 #define __NR_execveat		350
+#define __NR_waitfd		351
 
 #define NR_syscalls		351
 
diff --git a/arch/sparc/kernel/systbls_64.S b/arch/sparc/kernel/systbls_64.S
index d72f76ae70eba..8aee6e2d8e56d 100644
--- a/arch/sparc/kernel/systbls_64.S
+++ b/arch/sparc/kernel/systbls_64.S
@@ -168,4 +168,4 @@ sys_call_table:
 	.word sys_syncfs, sys_sendmmsg, sys_setns, sys_process_vm_readv, sys_process_vm_writev
 /*340*/	.word sys_kern_features, sys_kcmp, sys_finit_module, sys_sched_setattr, sys_sched_getattr
 	.word sys_renameat2, sys_seccomp, sys_getrandom, sys_memfd_create, sys_bpf
-/*350*/	.word sys64_execveat
+/*350*/	.word sys64_execveat, sys_waitfd
diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c
index 4798232494294..698ad91b10787 100644
--- a/arch/sparc/mm/fault_64.c
+++ b/arch/sparc/mm/fault_64.c
@@ -22,6 +22,7 @@
 #include <linux/kdebug.h>
 #include <linux/percpu.h>
 #include <linux/context_tracking.h>
+#include <linux/dtrace_os.h>
 
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -264,7 +265,9 @@ static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code,
 	}
 
 cannot_handle:
-	unhandled_fault (address, current, regs);
+	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, fault_code, 14,
+		       SIGKILL) != NOTIFY_STOP)
+		unhandled_fault (address, current, regs);
 }
 
 static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs)
@@ -326,6 +329,12 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
 	} else
 		flags |= FAULT_FLAG_USER;
 
+	/*
+	 * DTrace may want the page fault ignored...
+	 */
+	if (unlikely(dtrace_no_pf(regs)))
+		return;
+
 	/*
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..